Nordic is right; Delt and traps for most people seems to have the most androgen receptors..
think about nature and it makes.. 
I think a factor also is that many dudes who juice really have no idea how to train correctly with mind/muscle connection so they overuse their delts on chest etc,,,
what would you say is your most obstinate bodypart to grow Alex?? I would say for myself its calves, although genetically I just have small calves. Chest used to be one of my worst but after learning how to flex it properly and carrying that over into training, it grew well.